Phenology and host preferences Phlebotomus perniciosus (Diptera: Phlebotominae) in a focus of Toscana virus (TOSV) in South of France

Abstract

This paper reports on an entomological survey performed over the period 2009–2011 in endemic focus of peri-urban TOSV in South of France located from 24km east of Marseille. Sand flies were captured using CDC light traps set in sand fly resting places overnight, and temperature, relative humidity and wind were recorded to establish possible relations between meteorological factors and vector densities. The most common species, of 5,432 specimens collected and identified, was Phlebotomus perniciosus (74%), followed by Sergentomyia minuta (6%) and Phlebotomus ariasi (1%). Male flies were highly predominant for all Larroussius species instead of S. minuta which counted (85%) of females. The results shed light on the wide population’s dynamic of P. perniciosus in France showing a diphasic seasonal trend with two abundance peaks at the beginning of July and late August, when a mean temperature is from 23.3 to 25.7°C. Interestingly, these two peaks are corresponding to the peaks of occurrence of human TOSV cases. Among the 1724 females collected, 549 (32%) were blood-fed. Based on the results of blood meal analyses, P. perniciosus fed on large animal’s diversity (man, chicken, rabbit, others mammalians, etc.), including bats that are the only species found naturally infected by TOSV. Results indicate that host choice was probably related to its availability than specific attractiveness. Data presented confirm that sand flies easily adapted to the periurban sites like, P. perniciosus may represent a public health concern for pathogen transmission in similar Mediterranean environments.